When Casper's been being friendly lately even when playing with a boy named Jimmy, Kibosh: The King of the Underworld has Casper enrolled into a Scare School headed by the two-headed headmaster Alder and Dash. He befriends Ra, a mummy with unraveling issues and Mantha, a zombie girl who keeps falling apart. When Casper discovers the two-headed headmaster's plot to use a petrification potion to turn Kibosh into stone and take over the Underworld and Deedstown, he and his new friends must stop him.

Devon Werkheiseras Casper / Casper's Shadow (voice)
Brett DelBuonoas Jimmy (voice)
Jim Belushias Alder (voice)
Bob Sagetas Dash (voice)
John DiMaggioas Stinkie / Frankengymteacher (voice)
Billy Westas Fatso / Figurehead (voice)
Dan Castellanetaas Stretch (voice)
Kevin Michael Richardsonas Kibosh (voice)
Matthew Underwoodas Thatch (voice)
Christy Carlson Romanoas Mantha (voice)